Power transmission and control



V. A. FYNN.

POWER TRANSMlSSION AND CONIROL.

APPLICATION FILED MAY I. 1916- Patented Nov. 11, 1919.

2 SHEETSSHEET I.

WITNESS BY 6 654 w )IIIUHNEY V. A. FYNN.

2 SHEETS-SHEET 2.

Fig.3.

Speed Torque.

WITNESS y Inn Ego MUM/NE) 1 Patented Nov. 11, 1919.

UNITED STATES PATENT OFFICE.

VALERE A. FYNN, OF ST. LOUIS, MISSOURI, ASSIGNOR TO WAGNER ELECTRICMANU- FACTURING COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OFMISSOURI.

P'OWER TRANSMISSION AND CONTROL.

United States of America, have invented a certain new and useful Power'lransmission and Controh of which the following is such a full, clear,and exact description as will enable any one skilled in the art to whichit appertains to make and use the same, reference being had to theaccompany ng drawings, forming part of this specification.

My invention relates to the transmission of power and the controlthereof, more particularly in connection .with self-propelled vehiclesin which the prime mover is an nternal combustion engine.

Because tlie'torque of an internal combustion engine is very' small atlow speeds,

reaches a maximumwith increasing speed,

and then diminishes again, it has been found necessary to change thegear ratio between the engine and the wheels, in order to-start suchvehicles, to drive them over heavy roads or up steep grades. This changeis usually carried out by means of a hand-operated gear shifting lever.In order to dispense with this lever and gearing and the disadvantagesconnected therewith, and in order, also, to increase the number ofavailable gear ratios between engine and wheels, the substitution ofelectromagnetic variable ratio transmission apparatus for the mechanicalgearing has heretofore been proposed.

My invention relates to improvements in such electromagnetictransmission apparatus, and has for. its object to greatly sim-o plifythe necessaryoperations and the apparatus with which they are to becarried out.

My invention will be better understood by reference to the accompanyingdrawings, in which Figure 1 is a diagrammatic'representation of aknown.form of electromagnetic transmission to which my invention can beapplied. Fig. 2 shows one embodiment of said invention, and Fig. 3illustrates the results obtained. in actual practice by the use of thatform of the inventionwhich is shown in Fig. 2.

Referring to the drawings, I will more particularly describe myinvention as applied to that form of electromagnetic transmission Whichis sho n in F g 1.. In this Specification of Letters Patent.

Patented Nov. 11, 1919.

Application filed May 1, 1916. Serial No. 94,653.

figure, 2 represents the engine shaft to which is coupled the fieldstructure 3 of a dynamo electric machine the armature 4 of which iscoupled to the shaft 5 which drives the vehiclewheels 9, 10, through thedifferential 8. To this shaft is also coupled the armature (3 of asecond dynamo electric machine the field structure 7 of which isattached to the vehicle frame and is prevented i from revolving aboutthe armature 6 with which it cooperates. In order to operate such atransmission, the two dynamo electric machines are usually connected ,inseries, and means are provided for varying the field ampere turns of thegenerator, as well as those of the motor. The term generator? is usuallyapplied to that dynamo electric machine both members of which arerotatable, and the term motor to the one in which one of the members isstationary. In order to reduce the wheel speed and increase the torqueexerted by the latter, without being obliged to change the speed of theengine, it is necessary to increase the. motor excitation. The sameresult can, however, to

some extent, be achieved by decreasing the generator excitation, theeffect in this case being limited by the fact that a decrease of thegenerator excitationwill necessarily decrease the amount of powertransmitted.

The two methods can also be combined, in

order to achieve the desired results. After the drivenshaft has reacheda sufficiently high speed, it is usual to rely on the generator only andmake use of it as a dynamo electric coupling by short circuiting same onitself.

In order to apply this known form of control, it is necessary to makeuse of somewhat complicated switches and sometimes of several sets ofadjustable resistances.

In carrying my invention into practice,

I so proportion the generator and motor windings as to secure themaximum locked torque and the slowest revolution of thewheels 9, 10 whenthe windings of said machines are connected in series, as shown in Fig.2, and the auxiliary circuit including i the resistance 15 is open. Inorder to grad ually increase the speed of the driven shaft and reducethe maximum torque it exerts, I

'connect the resistance 15 across the terminals of the two machines, andgradually reduce same until it is entirely out out, at which time themotor will be idle and the enerator will e t n as a dynamo el coupling.transmitting the engine power to the wheels with but a negligible slip.In other words, I achieve my object by dimensioning both machines forthe lowest speed 5 and maximum torque of the wheels. and varying saidtorque and speed by creatinga shunt to the generator which includes apower consuming device, and by varying the amount of power consumedthereby. Fig. 3 shows the result of an actual test of that. form of theinvention which is shown in Fig. '2. In this figure, the foot poundstorquedeveloped at the wheels is plotted against the speed of saidwheels. With the generator and'motor connected as shown in Fig. 2, andwith a shunt of infinite resistance across the terminals of thegenerator, the ob- ,tainableperformance is sho'wn by curve 19.

It is seen that when the driven shaft is al- 2 lowed to run free. itreaches a speed of about 8O revolutions. \Vhen locked, its speed is, ofcourse, zero, and'it develops a torque of 212 foot pounds. Atintermediate speed the torque values are-as shown by the curve. Theperformance of the machine with .75 of an ohm in the shunt across thegenerator terminals is shown by the curve 21. It is seen that the lockedtorque is now but 176 foot pounds, while the free speed of the wheelshas risen to 118 revolutions. \Vith .44 of an ohm in the shunt acrossthe generator, the maximum or locked torque is 141 foot pounds and thefree speed is 196 revolutions,

as shown by curve 22. \Vith .3'of an ohm in the generator shunt, thelocked torque is 118 foot pounds, and the free speed is 262 revolutions,as shown by curve 23. With the generator short circuited, that is withall the resistance 15 cut out of the shunt circuit,

. 40 the generator acts as a'coupling, develops a locked torque of 65foot pounds and the free speed of the wheels rises to 338 revolutions.All these curves were obtained by keeping the engine speed constant aslong as possible. After a condition was reached where the fuel valve wasfully open, the speed of the" engine decreased, as indicated by thecurves, 24, 25 and 26, for the three values of the shunting resistanceused for the curves 23, 22 and 21 respectively.

Fig. 3 shows that the present invention makes it possible to graduallygo from the lowest speed to direct. drive with but little loss and bymeans of extremely simple and easily handled apparatus.

Having fully described my invention, what I claim as new and desire tosecure. by Letters Patent ot' the United States is:

.1. In an appazatus ot' the character de- 6 scribed, the combination ofa prime mover,

a driven shaft, :1 generator having one elementdriven by the prime moverand the other mechanically connected to the driven shaft, 21 motorconnected to receive electrical energy from the generator and having oneelement im chanically connected to the driven shaft. an auxiliarycircuit connected to the terminals of the generator in parallel with themotor. and means in said circuit for varying the amount of energyconsumed thereby.

2. In an apparatus of the character; described. the combinaion of aprime niover, a driven shaft. a generator having one element driven bythe prime mover and the other mechanically connected to the driven,shaft. a motor connected to receive electrical. energy from thegenerator and having one clement mechanically connected to the drivenshaft. and means for diverting from the motor a variable portion of thecurrent produced by the generator.

-1. In an apparatus of the character described. the combination ot-aprime mover, a driven shaft. a generator having oneelc ment driven bythe prime mover and the other mechanically connected to the drivenshaft. a motor connected to receive electrical energy from the generatorand having one element, mechanically comiected to the driven shaft. andanadjustable resistance connected to the, terminals of the generator inparallel with the motor.

' 4. III-3H1 apparatus of the character described, the combination of aprime mover, a driven shaft, a series generator having one elementdriven bythc prime mover and the other mechanically connected to thedriven shaft, a series motor connected to receive electrical energy fromthe generator and having-one clement mechanic.- illy connect-ed to thedriven shaft, an auxiliary circuit connected to the terminals of thegenerator in parallel with the motor, and means in said circuit forvarying the amount of energy consumed thereby. I

In an apparatus of the character described. the combination of a primemover, a driven shal't. a series generator having one element driven bythe prime mover and the other mechanically connected to the drivenshall, a series motor connected to reccive electrical energy fromthegenerator and having one element mechanically connectcd-lo the drivenshaft, and an adjustable resistance-connected to the terminals of thegcm-rator in pan'allel-wilh the motor.-

(i. in an apparatus of the. character described, thc. combination of aprime mover, av driven shaft. a generator having one. elemcnt driven bythe prime mover and the I other mechanically connected to the drivenshaft, a motor connected to receive electrical energy from the generatorand having one element mechanically connected to the driven shaft.mcans-l'or diverting from the motor a portion of the. current producedby the generator, and means for short circuiting the generator.

7. In an apparatus of the character described, the combination of aprime mover,

driven shaft, a generator having one element driven by the prime moverand the other mechanically connected to the driven shaft, a motorconnected to receive electrical energy from the generator and having oneelement mechanically connected to the driven shaft, :1 power consumingcircuit connected to the terminals of the generator in parallel with themotor, and a controller for varying the amount of power consumed by saidcircuit and short circuit-in the generator.

S, in an apparatus of the character described, the combination of aprimemover, a driven shaft, a generator having one element driven by theprime mover and the other mechanically connected to the driven shaft. amotor cormectcd to receive electrical energy from the generator andhaving one element mechanically connected to the driven shaft, and anadjustable power consuming device connected to the generator in parallelwith the motor.

9. In an apparatus of the character .described, the combination of aprime mover, a driven shaft, :1 series generator having one memberdriven by the prime mover and the other connected to the driven shaft, aseries motor in circuit with the generator and having one memberconnected to the prime mover, an auxiliary circuit, means forconnecting, said circuit to the generator in parallel with the motor.and means in said circuit for varying the amount energy consumedthereby, the relation between the'field ampere turns of the generatorand. motor being; such that their maximum con1- bined torque isdeveloped when the auxili ary circuit open.

10. 111 power transmiosion apparatus, the combination of two namoelectric inachines, a driven shaft, a mechanical connection between oneelement of each dynamo electric machine and the driven shaft, electricalconnections to transfer energy from an element of one dynamo electricmachine to an element of the other dynamo electric machine, an auxiliarycircuit con.- nected to the terminals of the interconnected elements ofthe dynamo electric machines,

and means for varying the amount of power consumed in said auxiliarycircuit.

In testimony whereof, I have hereunto my hand and aliixed my seal.

VALERIE A. FYNN. he

